Method for sterile packaging of articles

ABSTRACT

A QUANTITY OF SOLUTION HAVING A KNOWN CONCENTRATION OF ONE OF A GROUP OF ANTISEPTIC AGENTS IS SEALED TOGETHER WITH THE ARTICLE TO BE STERILIZED IN A FLEXIBLE, AIR-TIGHT CONTAINER, AND THEN THE ARTICLE AND CONTAINER ARE WORKED SO THAT THE ANTISEPTIC SOLUTION SATURATES THE EXPOSED SURFACES OF THE ARTICLE AND CONTACTS THE ENTIRE INTERIOR SURFACE OF THE CONTAINER. THE ENTIRE PACKAGE IS THEN HEATED   TO A TEMPERATURE IN THE RANGE 120*F. TO 212*F. FOR A PERIOD OF THREE TO TWENTY-FOUR HOURS, DEPENDING ON THE AGENT USE, AND SUFFICIENT TO KILL ALL BACTERIA, FUNGI, AND SPORES IN THE PACKAGE.

Nov. 9., 1971 F. c. MOORE ETAL METHOD FOR STERILE PACKAGING OF ARTICLES`2 Sheets-Sheet 1 Filed NOV. v4, 1969 Nov. 9, 1971 F, C, MQORE ETAL3,618,283

METHOD FOR STERILE PACKAGING OF ARTICLES Filed Nov.` 4, 1969 2sheets-sheet 2 l 5 32 y O g l?, 116 @5913' 1i l l //C/w/ cal/@If 38 u" m110 S 3o 9mm-.s @me United States Pate-'nt ce Patented Nov. 9, 1971 U.S.Cl. 53-21 FC 26 Claims ABSTRACT OF THE DISCLOSURE A quantity of solutionhaving a known concentration of one of a group of antiseptic agents issealed together with the article to be sterilized in a flexible,air-tight container; and then the article and container are worked sothat the antiseptic solution saturates the exposed surfaces of thearticle and contacts the entire interior surface of the container. Theentire package is then heated to a temperature in the range 120 F. to212 F. for a period of three to twenty-four hours, depending on theagent used, and suicient to kill all bacteria, fungi, and spores in thepackage.

RELATED APPLICATIONS This application is a continuation-in-part of anearlier application of Francis C. Moore and Leon R. Perkinson for Methodfor Sterile Packaging of Resilient, Absorbent Pads, S.N. 788,480, tiledJan. 2, 1969 (now abandoned) which is a continuation-in-part of anapplication of the same inventors for Method for Sterile Packaging ofResilient, Absorbent Pads, S.N. 725,826, led May 1, 1968 (nowabandoned).

BACKGROUND AND SUMMARY The present invention relates to a method ofpackaging articles such as resilient, absorbent pads or Sponges of thetype which might be used by a surgeon for scrubbing his hands inpreoperative procedure wherein the entire interior of the container andits contents are sterilized after it is sealed and remain sterile untilopened for use.

As is commonly known, the growing vegetative cells of most bacteria arekilled much more easily than are the spores of the same bacteria. In thepast, confusion has arisen by the use of the term sterilization orbactericidal to cover the situation wherein the vegetative cells aloneare killed. In the present application, the word sterilization is usedin its strict sense to mean a pro cedure that guarantees the destructionof all forms of microbial life so that the spores cannot be rejuvenatedby any known technique.

In publication No. 437 of the U.S. Public Health Service, part 73,73.37(e), sterilization is dened as the complete destruction ofcontaminating, living organisms, including living spores.

Another area requiring attention is the type of test used to determinewhether or not a thing is sterile. The sporicidal test recommended byThe Association of Oliicial Analytical Chemists suggest that for testorganisms, one species of a Clostridia or Baclli strains of Bacillussubstilis and Clostridium sporogenes should be employed. The testscarried out in determining the results of the present invention are inaccordance with the specification of the A.O.A.C. Procedure.

Although persons skilled in the art will readily appreciate that thepresent invention is not limited to the packaging of any particular typeof article but rather pertains to broad classes of articles such ascatheters, hypodermic needles, sutures, etc., nevertheless, theinvention will be described in detail in connection with the sterilepackaging of a surgeons scrub sponge wherein it is desired to include asufficient supply of soap in the package to permit a surgeon to conducta pre-operative scrub without adding water to the contents of thepackage after opening.

Heretofore, the principal methods for sterilizing solid articles priorto packaging include steam sterilization, dry-heat sterilization, gassterilization, sterilizing by irradiation, and fractional sterilization.Steam sterilization is carried out in an autoclave and employs saturatedsteam under pressure. There are many products which, of course, areincapable of withstanding such treatment. The temperature at whichautoclaves operate is usually 121 C. as measured by a thermometerlocated in the steam discharge line of the autoclave. Further, tosubject a sealed container to this temperature, a pressurized atmospherewould be required, so usually the articles are sterilized and thenpackaged aseptically.

Dry-heat sterilization is normally carried out in an oven specificallydesigned for the purpose. The oven may be heated by gas or electricity;but since dry heat is less eicient in sterilizing than moist heat,higher temperatures and longer periods of exposure are required thanwith autoclaving. Dry-heat sterilization is carried out frequently atl60-170 C. for a period of two to four hours. Again, it is assumed thatthe articles being sterilized are capable of withstanding suchtemperatures.

Gas sterilization requires specialized equipment designed for theparticular purpose; and if carried out prior to packaging, then thepackaging must be effected aseptically. Further, some procedures for gassterilization are not as eiective as others.

For example, although ethylene oxide has been widely accepted and hasreceived official recognition as a sterilizing agent, in reality itssterilizing capability varies widely with the procedure used. Acommercial process employing pre-humidiiication, heating and evacuationof the chamber, high concentrations of the gas and operating cycle aslong as twenty hours will result in sterilization. However, the ethyleneoxide sterilization methods being carried out in some hospitals andmedical offices are not nearly as reliable or eiective. See, for exampleDisinfection, Sterilization, and Preservation, Lawrence and Block (Leaand Febriger 1968), chapter 32. Further, gas sterilization isundesirable because of the formation of residuals as glycol in thepresence of water.

Techniques are available for the sterilization of some types ofpharmaceutical products by gamma rays and by cathode rays, but theapplication of such techniques is limited because the highly specializedequipment required and the harmfful eiects of irradiation on productsand their containers.

Fractional sterilization (or Tyndallization) requires the heating of thearticle on each of three or more successive days to a temperature highenough t0 kill vegetative cells, but insufficient to kill spores. Sporesthat germinate in the period between successive applications of heat arekilled, but the process is primarily suited to sterilization of liquids,and is not satisfactory for solutions containing non-n-utritive materialbecause bacterial spores may fail to germinate in these materials duringthe periods between heat treatments.

Wit-h regard to specific articles, surgeons scrub sponges containing adried soap to be used in cleansing the surgeons hands are known. Afterthese Sponges are impregnated with a soap solution, they are dried, andthen gas-sterilized (using ethylene oxide or propylene oxide) orsterilized by irradiation. When is is desired to use the sponge, watermust be added t put the soap into solution. However, it has been foundthat this method of sterilizing is not satisfactory in that it isdifficult to completely and reliably effect a bactericidal condition inthe packages of sponges using this method.

Although methods of sterilization other than gas sterilization aredesired for this purpose they have not proved successful. For example,it has been found that the steam sterilization of sealed packages ofarticles enclosed in conventional plastic containers will cause thecontainers to rupture at the temperatures induced. The heat causesexpansion of air trapped in the package, and the temperatures requiredin autoclaving increase the vapor pressure of liquids in the packageenough to cause it to rupture. The problem 0f trapped air becomes evenmore accentuated when the article desired to be packaged is a sponge, aswith the present invention. Those packages which are intended to besterilized by steam or heat usually have air-permeable containers sothat they must be sterilized just prior to use, or they are rststerilized and then packaged aseptically. The present invention, on theother hand, contemplates sterilization of the entire contents of thepackage after it has been sealed, and establishment of a bactericidalcondition that pervails until the package is opened for use.

In its broadest aspects, the present invention contemplates sealing anarticle in a flexible container with a predetermined amount of asterilizing agent in liquid form. Effective germicidal agents include asoap solution with 1 to 2% hexachlorophene, a solution of an iodophor, a3% solution of parachlorometahexanol, a 1 to 5% solution of Merthiolate,and an aqueous 3% solution of Zephiran. After sealing, the package iskneaded, rolled or otherwise worked in order to completely contact allinterior surfaces of the container and all exposed surfaces of thearticles with the germicidal solution. The package is then heated andheld within a temperature range below the boiling point of the liquidfor a predetermined time sufficient to destroy all bacteria, fungi, andspores. The time and temperature values depend to some extent on theconcentrations and agents used, but in any event rupture of the packageis prevented and a complete sterilization of the articles is effected.

In one embodiment, a predetermined amount of a liquid sterilizing orantiseptic agent is introduced into an envelope or at type of container.The pad or sponge which is to be packaged is also placed in thecontainer; and the container sides are then forced together so that itassumes a reduced volume. Thus, the antiseptic or germicidal agentcontacts the sponge, is absorbed by it, and most of the air is expelledfrom the container. Then the package is sealed, and further squeezed sothat the sponge assumes an even reduced volume and the antiseptic agentcompletely wets the interior of the sealed package.

When the sponge is then released, it will expand slightly therebyabsorbing substantially all of the antiseptic agent for subsequent use,yet leaving the entire package and its contents wet. The package is thenheated to destroy all bacteria, fungi and spores in it; and the packageremains sterilized until used.

In an alternative embodiment, a soap or detergent solution containing aliquid germicidal agent is deposited into the pad as it is conveyed downa line. Next, the pad is packaged in laminated flexible sheet materialhaving an interior coating of rubber-modified linear polyethylene. Thenthe package is squeezed so that the solution forms suds to contact theentire contents and interior walls of the package. Next, the package isheated at suflicient temperature and time to destroy all bacteria, fungiand spores in it; and enough liquid is retained by the pad for asurgical scrub when the package is opened for use.

In both 0f the above-described embodiments, the com- 4 bination ofgermicidal agent, container material and sterilization parameters permitthe establishment of a bactericidal condition in a sealed, air-tightpackage of a surgeons scrub sponge at sufficiently low temperature toavoid rupture of the container.

Thus, the inventive method provides a convenient, inexpensive, andreliable process for sterilizing articles and the inner surfaces of asealed, flexible container for the articles and for packaging thearticle with the assurance that the package and its contents will remainsterile during storage and shipment, and thereby be ready for use assoon as it is opened without additional sterilizing. At the same time,the package, in the case of the sponge, contains a sterilized soapsolution which may be used in cleaning and scrubbing a surgeons hands.

Other features and advantages of the present invention will be obviousto persons skilled in the art from the following detailed description ofa preferred embodiment accompanied by the attached drawing.

THE DRAWING FIGS. l-6 illustrate the various steps of one embodiment forpackaging a sponge according to the present invention; and

FIGS. 7-13 illustrate an alternative method of packaging according tothe present invention.

DETAILED DESCRIPTION Turning first to FIG. 1, there is seen a containeror bag generally designated 10 which preferably is made of two at sheetssealed together on three sides including a bottom 10a and two sides,thereby leaving an aperture at the top which is designated in thedrawing by reference numeral 11. The container is held in an uprightposition as shown `by apparatus which is not illustrated since it formsno part of the invention. The sheets are formed from any suitablematerial which has the properties of flexibility and liquid and gasimpermeability. The preferred sheet material (described in greaterdetail within) is a laminate with a rubber-modified linear polyethyleneinterior 12 with a Mylar backing 13. Polyethylene, or other heatscalable plastic material 14, may be applied about the inner portiondening the aperture 11.

A predetermined amount of liquid antiseptic agent 15 containing agermicide and a quantity of liquid soap or detergent is placed in thepouch-shaped container 10. While any suitable liquid germicide may beused, effective results have been obtained with hexachlorophene, havinga concentration in the range of between 0.2% to 10% by total liquidweight in a conventional liquid soap solution. For the packaging of asurgical scrub sponge, the soap solution may have a volume of between1.0 and 40 cc., a preferred formulation being about 4 cc. of liquid soapand 20 cc. of water. Other sterilizing or antiseptic agents may be used;but it is desired that the antiseptic agent not only be capable ofsterilizing the sponge and the inner surface of the bag after thepackage is sealed, but also of being used as thc cleansing solution withwhich a surgeon scrubs his hands.

A sponge generally designated 16 in FIG. 2 is also inserted into thecontainer 10 through the open end `11, and this may, of course, be donebefore or after the antiseptic agent is introduced.

The sponge 16 may be any resilient, absorbent scrub pad such as the onedisclosed in our co-pending application for Scrub Pad and Method ofMaking, filed May 1, 1968 Ser. No. 725,823 (now abandoned). It will beobvious, however, that the present invention is not so limited-it is amore general method for sterilized packaging of solid articles. Sincethe method results in the sterilization of the bags inner surface and ofthe bags contents, it is apparent that the pad, at the time of insertioninto the bag, may be in a non-sterile state.

Next, as seen in FIG. 3, first and second side pressure plates 17 and 18are forced together to reduce the volume of the package thereby forcingair from the interior of the container and causing the solution 15 topenetrate the sponge V16 and contact a substantial portion of theinterior surfaces of the container 10.

While the lvolume of the combination thus rendered as shown in FIG. 3,heated platens 19 and 20' (see FIG. 4) seal the polyethylene-coatedinterior sides of the foil 12 of the container. In the illustrationgiven, the level of the liquid antiseptic is below the top of thefliexible bag; however, it is to be understood that effective heatsealing may be accomplished even though the volume of the package isreduced to a point Where the antiseptic solution spills over the top.

The function of the next step is to insure that the antiseptic solutionhas contacted the entire interior of the sealed package and all exposedsurfaces of the article; and to accomplish this, the side pressureplates y1.7 and 18 further reduce the volume of the package and at leastpartially compress the sponge, thereby displacing some of the liquidantiseptic and causing the entire inner surface of the bag to be flushedwith the germidical solution (FIG. Y

.Even though the sealing step may trap a pocket of air within thecontainer (as at 21 in FIG. 4), or air may have been trapped in thesponge itself, the subsequent squeezing of the pad will cause the airand soap solution in the pad to form suds which will fill the upperpocket and contact the entire interior surface of the containersurrounding this pocket.

An alternative method for insuring that the antiseptic solution 15completely contacts or flushes the interior surface of the container andthe entire surface of the article is to force the package between tworotatable rollers, as in FIG. 5A wherein the rollers are designated 22and 23 and arranged to rotate about axes perpendicular to the plane ofthe drawing. Thus, the solution 15 will be partly forced from the sponge16 adjacent the surface being compressed; and it will form suds tocontact the entire interior surface of the container. Equivalnettechniques for working or kneading the sealed, flexible package will beapparent to persons skilled in the art.

Next, the plates 17 and 18 are released; and the resiliency of thesponge 116 causes it to assume a slightly expanded width, as illustratedin FIG. 6, and to re-absorb the excess antiseptic agent from the sidesof the package. This collapses the sidewalls of the container 10` aboutthe periphery of the sponge; and the antiseptic agent saturates thesponge and is thus stored in the sponge for subsequent use as a handcleansing agent. When the container 10` is torn open as it is desired touse the sponge 16, there is no excess spillage of the antiseptic agentsince it has impregnated the sponge 16; and further, substantially allof the antiseptic agent which had ordinarily been placed within thecontainer is available for use.

Finally, the package is heated to a sucient temperature and for asuflicient time to destroy all bacteria, fungi and spores within thepackage. Although the heating step is preferably carried out by theapplication of hot air to the sealed package, as illustratedschematically in FIG. 13, it will be appreciated that alternativeheating methods may be as equally effective. For example, radiant lampsand gas or electrically heated air may also be employed.

However, heating with hot air is preferred because it has been foundthat a completely bactericidal condition can be created within thepackage at unusually low temperatures with the antiseptic agents usedherein-thus eliminating the treat of rupture while insuring a germfreesponge.

Because air will ordinarily be trapped in the package (either in the paditself or in the peripheral interstices between the pad and thecontainer), the package Will expand slightly as it is heated, accordingto the temperature to which it is heated.

Turning now to FIGS. 7-13, an alternative and preferredpmethod ofsterile packaging the scrub pads will now be described in detail.

The sponge is generally designated by reference numeral 16, andindividual Sponges are conveyed along a conveyor 25 in the longitudinaldirection of the sponge 16. As the sponge 16 passes beneath an endportion of a conduit 26, which is connected to a source (not shown) ofthe antiseptic agent, the liquid antiseptic agent together with the soapor detergent solution, generally designated by reference numeral 27, isforced or squirted onto the top of the sponge. It has been found thatembedding a number of needles directly into the sponge enables theintroduction of larger quantities of the liquid in minimum time. Sincein preferred quantities, the amount of the germicidal agent released persponge is about 25-3'0 cc., and since the expanded dimensions of thesponge 16 may typically be 3'1/2 in. by 21/2 in. by 11/2 in., the entirevolume of antiseptic agent is held by the sponge.

The sponge is then conveyed, as seen in FIG. 8, to an area where it isplaced on a flat sheet of the container material generally designated28. In this embodiment, the container material 28 is a laminate havingan upper layer (which is to become the interior surface of the finishedpackage) of a rubber-modified linear polyethylene extruded film such asthe butadiene-modified linear polyethylene lm marketed under the tradename Visotherm and manufactured by the Visqueen Company of Terre Haute,Ind. This type of material has a very high melting point; and eventhough it is heated for an extended period, it will not crack easily,thereby retaining its liquid and gas impermeability for long periods oftime. Further, it is heat scalable.

The polyethylene film 29 may be backed with any suitable non-porous andsubstantially non-stretchable yet flexible sheet material 30 such asMylar, paper, cellophane, or metal foil (or combination paper and foil).The outer layer functions as a non-stretchable shell which is capable ofwithstanding the internal pressures developed during heat sterilization.The butadiene-modified linear polyethylene serves as a non-rupturingliner and appears to conform to the surface irregularities and wrinklesof the non-stretchable outer layer without giving way under the forcesexerted at the temperatures of interest.

As seen from the side of FIG. 8', the sponge is conveyed longitudinallyand the sides of the container material 30 are folded up and around thesponge 16 as seen in FIG. 9. Adjacent edges are then brought intocontact with each other to form an overlapping area above the sponge -16as at 32. The overlapping portions are then heat-sealed together bymeans of heated plates 33 and 34 exerting opposing force against theoverlapping edges 32. Alternatively, conventional molecular Weightpolyethylene may be used as an interior coating on the rubber-modifiedpolyethylene to form the gas and liquid impermeable seal by heating.

After the seal is formed longitudinally of the container so that itappears to be a continuous tube, similar heat plates 36 and 37 (see FIG.l0) are lowered transverse of the tube to seal the package at both ends.Adjacent packages are then separated by cutting the tube transverselyand mid-Way of the transverse heat-sealed region so as to form end sealsfor each of the two adjacent packages. Alternatively, the individualpackages could be severed prior to the transverse heat sealing.

In the transverse heat sealing, the overlapping edges 32 of thecontainer 30 are folded over to lie at against the exterior of thecontainer. Turning now to FIG. l1, the transverse heat-sealed areas aredesignated 38 and 39; and as previously mentioned, the overlapping edges32 which extend longitudinally of the tube are also heatsealed. Thus,FIG. l1 is a top view of the sponge containing the aniseptic orgermicidal agent after it has been packaged in an impermeable containerof exible sheet material.

Turning now to FIG. 12, a pressure plate 40 is then forced into contactwith the sponge to flatten it by about one-half its original depth, andthereby extract the antiseptic scrub solution and trapped air from thesponge in the form of a frothy suds which fills the interstices 41 and42 at either end of the sponge as well as the side interstices andcontacts the entire interior of the package. The exact pressure appliedin order to accomplish the desired result depends upon the size of thesponge and upon its composition. However, for -25 cc. of soap solutioncontaining hexachlorophene as described below, and with a three-layeredsponge as described in the aboveidentified, co-pending applicationhaving a central layer of a resilient plastic foam which hasapproximately 60 cells or pores per lineal inch, sufficient suds aregenerated to entirely fill the package by compressing the sponge toabout one-half its original height. The higher pore density of thecentral layer causes better sudzing action.

When the pressure is released and plate 40 removed from contact with thepackage, the resiliency of the sponge will force it to its originalshape, thereby partially collapsing the package and reducing the volumeof the end interstices 41 and 42. The sponge re-absorbs the antisepticagent and holds it for further use. However, enough of the antisepticagent remains in contact with the interior of the container to effect abactericidal condition within the package when it is heated. Referringnow to FIG. 13, an oven cavity is denoted by reference numeral 34, andit is provided with electrical heating coils 46 for heating the air inthe chamber 45. The time and temperature of the heating step will, ofcourse, depend upon many variables; but the most significant factors arethe type, quantity and concentration of the antiseptic or germicidalagent used. Thus, the time and temperature sufiicient to destroy allbacteria, fungi and spores are best determined empirically, allowing asufficient margin for reliability.

Once the entire interior of the package has been wet or contacted by theantiseptic agent, the heating step should take place as soon as possiblethereafter to insureI the heating of the container and its contentswhile they are wet with the antiseptic agent. This has been found toreduce the heating temperature because sterilization of dry surfaces byheat takes a much longer time.

As just mentioned, the temperature at which the package is heated andthe time during which it is heated depend upon the type of antisepticagent employed, but it has been found that in any case, the temperatureshould be within the range of 120 F. and 212 F.; and it should be atleast about minutes in time. The following example will afford a greaterappreciation of this step in the process.

EXAMPLE I Standard laboratory sterility tests (i.e. the aboveidentifiedsporicidal test of the A.O.A.C.) were performed on wet scrub pads sealedin plastic film containers and prepared according to the inventivemethod. The pads were the multiple-layer, pillow-shaped spongesdescribed in the above-described, copending application. Each packagecontained approximately 22 cc. 3% Hexa-Germ, a chlorophene-baseantiseptic soap solution marketed by Huntington Laboratories,Huntington, Ind. In a first set of three of these packages, strips ofBacillus subtilis (globigii) spores were placed in the packages, whichwere then sealed, agitated and heated to a temperature maintainedbetween 164 F. and 174 F. for a period of 8 hours.

Laboratory findings indicated that bacterial growth in various dilutionsof the specimens after an incubation period was negative; and nomicrobic colonies were visible for an observation period of seven days,at which time the test was discontinued.

A second set of five packages containing the same spores were placed inan oven for about 71/2 hours where- 8 in the oven temperature wasmaintained between 173 F. and 183 F. Again, the findings indicated thatbacterial growth after an incubation period was negative; and nomicrobic colonies were visible during an observation period of sevendays.

EXAMPLE II For packaging a surgical sponge of the type described,preferred hexachlorophene antiseptic solution includes 27 cc. of waterand 8 cc. of hexachlorophene antiseptic soap solution marketed under thetrademark Dermasurgical by S. M. Edison Chemical Company, Jersey City,NJ. which contains a buffering agent for bringing the pH level down toabout 4.5. Using this germicidal agent, a preferred temperature range is165 (plus or minus 5) for a period of eighteen hours. Sterility is alsoachieved with this antiseptic agent in a period of six hours if thetemperature is raised to 180 F.

If the amount of hexachlorophene is doubled, satisfactory results havebeen obtained with temperatures as low as 130 F. and heating time of tenhours. Again, laboratory findings indicate that bacterial growth invarious solutions of the specimens after an incubation period of 7 dayswas negative.

EXAMPLE III In another sampling, the Sponges were impregnated with about25 cc. of an aqueous solution of iodine-base (iodophor) soap, marketedunder the designation Surgidine 'by Carter-Wallace, Inc., Cranbury, NewJersey, when diluted as directed. Strips of Bacillus subtilis (globgii)spores were again placed in tive sample packages. These packages wereheated to a temperature of 150 F. for two hours. The strips of Bacillusglobigii spores were resubcultured immediately upon removal from theoven; and no growth was obtained in any of the tubes containing thestrips.

Satisfactory results have been obtained with the iodophor germicide andtemperature ranges of 13G-140 F. for a period of 6 hours.

EXAMPLE IV In still another sampling, the surgical Sponges were sealedin a flexible container with 30 cc. of a soap solution containing 3% ofa germicide sold under the mark PCMX (pharachlorometahexanolmanufactured by Ottawa `Chemical Company, Toledo, Ohio) at a temperaturerange of 13G-140 F. for a period of 10 hours.

It is felt that a concentration range of 1-6% would be effective toinsure sterility with a temperature above about F. and heating periodsin the range of 8 to 20 hours, depending on the concentration andtemperature.

EXAMPLE V An aqueous solution with 1 to 5% sodiumethylmercurithiosoalicylate, marketed under the designation Merthiolateby Eli Lilly & Company, Indianapolis, Indiana, has been found to beeffective to sterilize the interior of the package if heated to atemperature of 140 for a period of 6 hours. lf the heating period isextended to as long as 20 hours, the temperature could be reduced to F.

EXAMPLE VI In the sterile packaging of a pre-operative swab, an aqueoussolution of Zephiran (a benzalkonium chloride solution manufactured byWinthrop Laboratories, Inc., New York, New York) is effective if heatedto a temperature within the range of 16C-170 F. for a period of 18hours.

The inventive procedure thus provides a convenient, economical andreliable method for sterile packaging of scrub Sponges. Having thusdescribed in detail two alternative embodiments of the inventiontogether with examples, it will be apparent to persons skilled in theart that certain of the steps described may be modified in sequence andthat equivalents may be substituted for the processes and componentsdescribed without departing from the principle of the invention. It is,therefore, intended that all such modifications and substitutions becovered as they embrace within the spirit Iand scope of the appendedclaims.

rWhat is claimed is:

1. A method of sterile packaging of an article comprising sealing saidarticle in a flexible container with a predetermined amount of a liquidsterilizing agent selected from the group consisting of hexachlorophene,iodophor, parachlorometahexanol, sodium ethylmercurithiosalicylate andbenzalkonium chloride; flexing the walls of the sealed package tocontact the entire interior surface of said container and exposedsurface of said article with said agent; and heating said package at atemperature in the range of l20212 F. and for a period of time in excessof 30 minutes to sterilize said article and the interior of saidcontainer.

2. The method of claim 1 wherein said agent comprises a soap solution ofl-6% hexachlorophene and wherein said sealed package is heated to Iatemperature within the range of 140-170" F. for a time between 14 and 20hours and sufficient to destroy all spores.

3. The method of claim 1 wherein said agent comprises an aqueoussolution of iodophor, and wherein said package is heated to atemperature within the range of 130- 150 F. for a period of 4-15 hoursand suiicient to destroy all spores.

4. The method of claim 1 wherein said agent includes about 3%parachlorometahexanol, and said package is heated to a temperaturewithin the range of 13G-140 F. for a period of 10-15 hours andsuflicient to destroy all spores.

5. The method of claim 1 wherein said germicidal agent comprises asolution of l-5% sodium ethylmercurithiosalicylate and wherein saidpackage is heated to a temperature in the range of 14C-160 F. for aperiod of -20 hours and suicient to destroy all spores.

6. The method of claim 1 wherein said germicidal agent is a benzalkoniumchloride solution of 1 3 concentration, and wherein said package isheated to a temperature in the range of 140-160 F. for a period of 14-20hours and suliicient to destroy =all spores.

7. A method of sterile packaging of resilient, liquidabsorbent padscomprising: applying a predetermined amount of liquid antiseptic agentto said pad whereby said agent is absorbed by said pad; sealing said padand said absorbed agent in a flexible, impermeable container; thenextracting said liquid agent from said pad while in said container tocause said agent to thoroughly contact the interior surface of saidcontainer; and heating the sealed package to a temperature below theboiling point of said liquid while said agent is in contact with theinterior surface of said container and for a sufficient time to destroyall bacteria, fungi and spores in said container.

8. The method of claim 7 wherein said first-named step comprises:placing a predetermined amount of said liquid antiseptic agent in aflexible container having a scalable opening; inserting said pad intosaid container; partially compressing said container to assume a reducedvolume, thereby expelling air from said container through said openingand causing said antiseptic agent to contact said pad; said step ofsealing comprising then sealing said opening while the container is thusreduced in volume.

9. The method of claim 7 wherein said step of extracting comprises thenfurther compressing said container and said resilient pad to cause saidantiseptic agent to be squeezed from said pad and thoroughly contact theinside of said container.

10. The method of claim 9 further comprising after said step ofpressing, the step of relieving compressive forces from said containerand said pad whereupon said pad eX- l0 pands and absorbs substantiallyall of the excess of said antiseptic agent in said container, leavingthe interior surface thereof wet.

11. The method of claim 7 wherein said predetermined amount ofantiseptic agent is between l0 cc. and 40 cc. of a surgical scrubsolution.

12. The method of claim 11 wherein said scrub solution container isbetween 0.2 and l0 percent hexachlorophene.

13. The method of claim 11 wherein said scrub solution is a detergentand said antispectc agent is an odophor.

14. The method of claim 7 wherein said first-named step includessquirting a predetermined amount of said antiseptic agent on said pad.

15. The method of claim 14 wherein said step of sealing includes placingsaid pad containing said antiseptic agent on a resilient, flexible sheethaving one surface of heat-sealable material, pressing overlapping edgesof said material together with heated members to form a tube about saidpad, and pressing facing surfaces of said tube together while heating ina direction transverse of said tube to form seals at the ends thereof.

16. The method of claim 15 wherein said step of extracting comprisessqueezing said package to force air and said solution in said pad toform a frothy suds to ll all interstices in said package.

17. The method of claim 15 further comprising the step of cuttingadjacent packages along said transverse heat seals to provideheat-sealed edges for both adjacent packages.

18. The method of claim 17 wherein said antiseptic agent is between l0cc. and 40 cc. of a surgical scrub solution containing between 0.2 and10 percent hexachlorophene.

19. The method of claim 18 wherein said step of heating comprisesraising the temperature of said package to at least 150 F. for at leastabout eight hours and sufficient to destroy all spores.

20. The method of claim 15 wherein said antiseptic agent is between 1cc. and 30 cc. of an iodophor base detergent.

21. The method of claim 20 wherein said step of heating comprisesraising the temperature of said package to at least about F. for atleast about two hours and sutiicient to destroy all spores.

22. In a method of forming a sterile package containing a resilient padimpregnated with a liquid surgical scrub solution, the steps of bringinginto contact a substantially dry, resilient, and liquid-absorbable padand a. -germicidal liquid scrub solution so that said pad absorbs apredetermined amount of said solution; then sealing said pad holdingsaid scrub solution in a flexible container; then flushing the entireinner surfaces of said container with the germicidal scrub solutioncontained therein to contact the entire inner surface of said containerand said pad with the germicidal'solution, and then heating the sealedpackage to a temperature less than the boiling point of said solutionfor a period suicient to kill all organisms in said sealed package. v

23. The method of claim 22 in which said flushmg step comprises workingsaid pad and container to redistribute the germicidal scrub solutionwithin the contalner and force the solution into contact with said innersurface of said container.

24. The method of claim 23 wherein said step of working said pad ischaracterized by the formation of suds by forcing air and soap solutionfrom said paid thereby to fill any interstices with the frothygermicidal scrub solution.

25. The method of claim 24 wherein the step of heating said sealedpackage while the interior of said container is Wet with said germicidalscrub solution to destroy all bacteria, spore and fungi in said package.

26. A method of sterile packaging of an article comprising sealing saidarticle in a llexible containervwith a References Cited predeterminedamount of a liquid sterilizing agent therein; UNITED STATES PATENTSexing the walls of the sealed container to contact the entire interiorsurface of said container and the surfaces 3,348,905 10/1967 RPVBIY53-21 X of said article with said liquid sterilizing agent; and heat- 5313991955 9/1968 Zlmmerman 21-58 ing said container and its contents ata temperature below the boiling point of said liquid agent and in therange of TRAVIS s MCGEHEE Pnmary Examiner 1Z0-212 F. for a period inexcess of 30 minutes to U S C1 X R sterilize the interior of saidcontainer and the containers contents. 10 21-58; 53-25

